This invention relates to air flow duct connectors as for use on clothes dryers and the like.
Air flow duct systems for venting exhaust air from clothes dryers must adapt to a variety of physical positions between the dryer air outlet and the opening in the adjacent wall. This is because each installation typically encounters a different lateral spacing between the outlet on the dryer and the opening in the wall. One duct component which is used to accommodate certain of these dimensional relationships is a telescopically expandable and contractible, two-piece tube assembly with side openings, sometimes called a "periscope" connector because of its visual resemblance to an actual optical periscope. This type of connector is advantageous in allowing the dryer to be located close to the wall, e.g., at about a two inch spacing. This type of connector is formed of two tubes which are telescopically interfitted, each having a lateral orifice and sleeve. There is a definite limit in the amount of contraction possible with these known commercial connectors because the sleeve abuts the end of the other tube. Thus, if the dryer outlet is displaced laterally only a few inches, or down to a fraction of an inch, from the wall opening, or even partially overlaps the wall opening, a periscope connector cannot normally be employed. Moreover, the dryer outlet is almost invariably somewhat offset from the wall opening. Therefore, connecting the dryer to the outlet with a proper metal connector meeting fire safety standards can present a significant problem. A typical type of telescopic connector is shown in U.S. Pat. No. Del. 218,825 to Blumer. Use of such a typical telescopic connector on a gas range is shown in U.S. Pat. No. 2,044,761 to Becvar. As will be noted, the minimum spacing between the air flow openings is a function of the maximum spacing of the openings.
What is needed in the trade is a telescopic air flow duct connector capable of having its inlet and outlet openings variably movable from a significantly wide spacing down to a small spacing and even a zero spacing, i.e., aligned with each other, so as to even accommodate any incremental spacing between these two extremes. Moreover, at all of these positions there must not be any significant dead air space adjacent the openings, or lint will collect there and present a potential fire hazard. Applicants are aware of stove pipe teachings as in Bell U.S. Pat. No. 31,652 (1861) and Neilson U.S. Pat. No. 258,311 (1882) which set forth special stove pipes potentially capable of a zero spacing at the openings, but these have significant resulting dead air spaces unsuitable for safe use with a clothes dryer because of the lint collection potential fire hazard.